1. Field of the Invention
This invention relates to a torque variation absorbing device which is used to take up and compensate for variations in torque fluctuations, and more particularly to a torque variation absorbing device which is installed on or connected to a crankshaft of an internal combustion engine to take up and compensate torque fluctuations produced by operation of the internal combustion engine.
2. Description of the Prior Art
A conventional torque variation absorbing device is disclosed, for example, in U.S. Pat. No. 4,663,983, issued on Feb. 12, 1987. As shown in FIG. 6 and FIG. 7, the conventional device includes a driving plate 50 attached or connected to an output shaft of an engine crankshaft 51 and a flywheel 52 which is located close to the driving plate 50.
As seen from FIG. 6, a spring mechanism 53 and a hysteresis mechanism 54 are located or positioned between the driving plate 50 and the flywheel 52. A damping and torque limiting mechanism 55 is located radially interiorly of the spring mechanism 53. In the conventional device, rotation of the engine crankshaft 51 and the torque fluctuation is transmitted to the flywheel 52 through the driving plate 50, the spring mechanism 53 and the hysteresis mechanism 54, which comprise the torque variation absorbing device. Thus, the torque variation is absorbed by the variation absorbing device.
The hysteresis mechanism 54 is located further radially interiorly of the torque limiting mechanism 55 and between the driving plate 50 and the flywheel 52. FIG. 7 illustrates the hysteresis mechanism 54 in greater detail. As seen from FIG. 7, a hysteresis plate 56, provided with a friction lining 56a of abrasive material, is partially bent and formed into a bent portion 56b. The bent portion 56b is fitted into a hole 57 bored or otherwise provided in the side plate 50b of the driving plate 50, thereby circumferentially fixing the hysteresis plate 56 to the driving plate 50. A cap 59 is fitted or otherwise positioned in the hole 57 of the side plate 50b. Likewise, the bent portion 56b of the hysteresis plate 56 is fitted in a hole 60 of the cap 59. A cone spring 58 and a ring 61 are installed between the hysteresis plate 56 and the side plate 50b. The ring 61 is installed between the cone spring 58 and the side plate 50b, thereby pressing the friction lining between the friction lining 56a and the flywheel 52 and producing a hysteresis. In the prior art device, a bolt hole 62 receives bolt 63 which extends to the sliding friction surface.
In the prior art, the friction lining 56a is provided beside the hysteresis plate 56. As to this arrangement, when the abraded dust of the friction lining is produced or released, the bent portion 56b will be hindered for the exclusion of the friction lining.